Electromagnetic operator



March 16, 1948. w. A. RAY 2,437,893

ELECTROMAGNETIC OPERATOR Filed April 13, 1943 M/ILL/AM ,4. PAY,

Inventor;

orgy, mains: 'yet"the""structure of alternating current"clectrornagnets'presentssomebomplicati'ons. Ac- *cordingl'y, it hasbeen'proposed to rectify the al- 'ternating current and to-operate'adirect current ensue-magnate the rectified current; A sim- Patented Mar.16, 1948 ELECTROMAGNETIC OPERATOR William A; Ray,= Glendale, Caliii,assignor to General Controls a corporation Application April 13, 1943,Serial No; 482,850

v 8 Claims. 1

* This invention relates to an 'electromagnet, and

' especially "to onethat is utilized for applying a magnetic force-tomovean operator.--Such an op- "erator, forexai'nple, may b'e'usedtocontrol a valve. Electromagnets forsuch purposes are now.

- incomrnon use. "These -electromagnets usually employ a movable plungerorarmature that serves to-applytheforceto ano'perator.

' "It is necessary- -to"piovide an electromagnetariavingsufiicient'powertomove the-plunger or' armature rapidlyt'o-theenergizedposition; yet 1 sucnpower is unnecessary merely to holdthe opera'tor in'that position; Once energized, the pow- 'erofthe'ele'ct'romag'net may be materially rednced-withou't-danger ofr'novementof the plunger or' armature" to-de en'erg'ized position. Allthisiswell'understoodt it is"-'referred to herein because oneaspectofth'einvention'relates to the control oi-the'p'ower'ofthe'electromagnet.

In-such magnets, it"has"been-common, in the pastgto' provide acondenser'in parallel with the coil of the electromagnetfwhen the circuit is vinterruptedftlie inductivekick of the coil is abs'oroed bythecondenser,andsparking at the-contacts is materially-reduced.

It is an object or this invention to make it possiblead-obtainthe'advantages of such a condenswhen theelectromagnetiis'-d'e=en'ergized. Since tli'e"seconda1'y coil isnot'short'circuiteddurin the'pe'riod when the armature orplun'ger is moving' to attracted position, it is-ensured that the initial rushofcurrent to the elec'tromagnet will notinduce "a""-destructivelyheavycurrent in the secondarycoil.

- It smother-o jector thisinvention to make it v possible to'use ag'coilto perform-the dual function of supplementing thep'o'werof theelectromagnet during'the major portion; of-the' stroke, and of providingthe short circuited coil thereafter.

It is advantageous to beable to operate an elecai ne't'fromavailablesources of electrical en such ascommerciar alternating current ple' iormof re'ctifierfsu'cli as "dry disc type, producesF-a riulsating cwent-game there is some likelihood cf'pr'odocing enatter -wh'en': thearmature or pl uri'g'r isin attractedposition.

It is another object of thls'inventi'onieto provide anelectromagnet-capableof" operating; .on a pulsating current, and thatis-'relativelyzfree'iof chatter. This object is zaccomplished by, theshort-circuited coil; which hastheefiectrof steadying the fluxthroughthe :core.

This invention possesses 1 many other. advantages, and has other objectswhich may be ,made

more easily apparent from.aconslderation of;one

embodiment of the inventioni For :thislpurpose there is shown a 'form intheidrawingsaccompanying and forming part of thelpresentspecification.The form will n0w=be describeindetail, illustratin the generalprinciples of thezinvention; but it is to-be understoodthatthisfietaileddescription is not to be taken in a limiting-sense, since the'scope ofthis invention isbestdefined by the appended claims.

Referring to the drawing,theasinglefigure is a wiring diagram of acircuit,- including anioperator that embodies the invention.

In the present instance-there is shown'an electromagnet I having a coreH. The core is diagrammatically illustrated asone having a :pair ofarms, provided with the pole pieces 2-x-and 3. These polepiecesco-operate with a movable armature i. The armatured may-beprovided with a stem or operating membericonnectedyforexample, to a loadto beoperated." The. member 5, for examplamay be thestem of a valve tobe. operated by the electromagnet I.

In order to attract the armature-4 and tomeve it into contact with thepole pieces :2 and .3, energizing coils are'provided on thecore II. Thecore l! thus carries a coil .6,=:arranged-inthe present instance tobeoperatedby asource of a1- ternating current toxwhichmains: 25 and'ZGmay be connected. However, the electromagnet .l: is arranged foroperating oddirectcurrent; and, for that reason, a rectifier'Sisincludedvbetween mains 25 and ZG-andthe coil 6. This rectifier 9 maybe of a conventional dry disc variety having stacks of discs forming aclosed bridge circuit.

The coil 6 may be connected directly to the diagonal points T and 8oftthevrectifier":bridge; and the mains 25 and-'26 :maybe connectedthrough a switch 12 to the 0therdiagonalpoints i3 and it; The'magnetomotive force produced by the coil 6 is temporarily augmented-or.supplemented in order to assist int-pulling the armature 4 to thepole-piecesland 3." However, as soon as the armature 4-imoves awayfrom-its unattracted position, thetsupplemental:magnetomotive force isdiscontinued.

In order to obtain this-'ivresultfzuse. is made of functions:

3 a supplemental coil I 4, placed on core H in assisting relation to thecoil 6. With the switch l2 closed and the armature 4 not yet startedfrom its unattracted position, the circuit for coil [4 is completedthrough the following path: From diagonal point I of the rectifier 9, tothe right hand terminal l5 of the coil [4, through the coil I l, lefthand terminal l6, connection l'l, contact arm l8, contact I9 carried bythe arm l8, stationary contact point 20, and a connection 2%, to theopposite diagonal point B. The arm i8 is shown as eangularly moved inresponse to the movement of the armature 4, and, for this purpose, mayhave its left hand end pivoted at 2'! to the stem 5. Thus, when thearmature A is in the unattracted position, the arm l8, appropriatelypivotally supported on standard 22, is in a position such as to maintaincontact between contact points l9 and 20. As soon as the armature A isattracted and moves away from its unattracted position, contacts I 9 and20 separate,.and coil, M is no longer eiiective to assist or supplementthe coil 6.

Accordingly, by this means, a high inrush of electric energy isprovided, to ensure that the armature ll will be attracted with a forcestrong enough to pull it into contact with the poles 2 and 3. When thearmature 4 arrives at, or near, the fully attracted position, themagnetomotive force required merely to hold it in that position can bereduced; and this is accomplished by the de-energization of coil I4.

Opening the switch 52 after the electromagnet l has been energized wouldresult in harmful arcing and sparking at the switch contacts. Breakingof a circuit in which there is a heavy inductance, such as the coil 6,is attended with these difiiculties, since the induction of the circuittends to maintain an arc across the contacts a condenser is obviated.Instead, the arrangement is such that the coil l4, after its temporaryenergization, is short-circuited to absorb the inductive kick.Short-circuiting of the coil it can be accomplished by the aid of acontact point '23 carried on the lower part of the arm l8, and aco-operatin stationary contact point 24. Thus, when the armature 4approaches its attracted position, contact points 23 and 24 engage andthe coil M is short-circuited through these two contacts. The completeshort-circuit includes the right hand terminal l5 of coil l4, contacts24 and 23, arm l8, connection I1, and left hand terminal l8. 2

' This short-circuit persists until the armature 4 begins to drop awayfrom the pole pieces 2 and 3 upon de-energization of the coil 14.Accordingly, when switch i2 is opened, .a substantial part of theinductive kick is absorbed in the coil is.

Since the coil [4 is shorted while the electromagnet l is energized, itserves, as heretofore stated, to reduce the fluctuations of themagnetism in core ll. Coil [4 thus serves three first, temporarily toaugment the power of the electromagnet; then to provide a circuit thatreduces the self-inductance of the holding coil 5; and, lastly, tosmooth out the variations in magnetism in the core ll.

The inventor claims 1 1. In an electromagnet,- a magnetic member adaptedto be influenced by a magnetomotive force to move from an unattractedposition to an attracted position, a coil adapted to be connected to asource of electrical energy, another coil also adapted to be connectedto said source, and magnetically coupled in cumulative relation to saidfirst coil and connected to said source in parallel with the first coil,and means operated in response to substantial movement of said memberfrom its unattracted position for successively disconnecting said othercoil for parallel arrangement and short-circuiting the said other coil.

. 2. In an electromagnet, a magnetic member adapted to be influenced bya magnetomotive force to move from an unattracted position to anattracted position, a coil adapted to be connected to a source ofelectrical energy, another coil also adapted to be connected to saidsource, and magnetically coupled in cumulative relation to said firstcoil and connected to said source in parallel with the first coil, andmeans operated in response to substantial movement of said member fromits unattracted position for short-oircuiting the said other coil, saidshort-circuiting means bein arranged to open the circuit of the saidother coil when the member moves away from its attracted position.

3. In an electromagnet, a magnetic member adapted to be influenced by amagnetomotive force to move from an unattracted position to an attractedposition, a pair of coils in cumulative relation and adapted to beconnected to a source of pulsating electrical energy to cause saidmember to be attracted, and means operated in response to movement ofsaid member from its unattracted position for disconnecting one only ofthe coils from the source and for thereafter short-circuiting said onecoil.

4. In an electromagnet, a magnetic member adapted to be influenced by amagnetomotive force to move from an unattracted position to an attractedposition, a pair of coils in cumulative relation and adapted to beconnected to a source of pulsating electrical energy to cause saidmember to be attracted, and means operated in response to movement ofsaid member from its unattracted position for disconnecting one only ofthe coils from the source and for thereafter short-circuiting said onecoil, said means being arranged to'open the short-circuit of said one ofthe coils when the member moves away from its attracted position.

5. In an electromagnet, a magnetic core, a pair of coils disposed on thecore in cumulative relation, a magnetic member co-operating with thecore and arranged to be moved from an unattracted to an attractedposition, a source of pulsating current for energizing said coils, and acircuit controller operated by movement of said member in response toenergization of the coils for de-energizing one only of the coils whensaid member moves away from its unattracted position, as well as forthereafter short-circuiting said one of the coils.

6. In combination, a full wave rectifier having an input adapted to beconnected to a source of alternating current, a first coil adapted to beconnected to the output side of the rectifier, a magnetic member movableto an attracted position when said coil is energized, a second coilwound cumulatively with said first coil, and

adapted to be connected to said-rectifier, and

means operated in response to movement of said member toward itsattracted position for disconnecting said second coil from the rectifierand 5 for thereafter short-circuiting said second coil.

7. In combination, a full wave rectifier, means for optionallyconnecting the input of said rectifier to a source of alternatingcurrent, an electromagnet including a first coil connected to the outputof said rectifier, and a second coil wound in assisting relation to thefirst coil, a magnetic member adapted to be moved from an unattractedposition to an attracted position and to be retained in said attractedposition upon energization of said magnet, and means operated inresponse to movement of said member for connecting said second coil tothe output of said rectifier when the member is in its unattractedposition and for short-circuiting the second coil when the member is inits attracted position.

8. In combination, an electromagnet having a first coil and a secondcoil wound in assisting relation, a magnetic member adapted to beinfluenced by said magnet to move from an unattracted position to anattracted position, switch means for connecting said second coil to asource of electrical energy and means operating in response to movementof said member for shortcircuiting said second coil when said member isin its attracted position.

WILLIAM A. RAY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 954,745 Larsen Apr. 12, 19101,005,856 Linquist Oct. 17, 1911 1,717,247 Perry June 11, 1929 1,742,367Nettleton June 11, 1929 1,978,737 Bower et a1 Oct. 30, 1934 1,979,127Warrick Oct. 30, 1934 2,001,494 Jones May 14, 1935 2,274,013 SwensonFeb. 24, 1942 FOREIGN PAIENTS Number Country Date 284,409 Germany May21, 1915

